Longitudinal links between adolescent siblings' gender-typed characteristics and sibling relationship quality: A dyadic approach

Sibling relationships have unique implications for youth well-being and adjustment, leading researchers to examine factors, such as sibling sex, that explain variation in sibling dynamics. This study was designed to unpack biological sex to examine girls' and boys' gender-typed personality qualities to determine whether they accounted for differences in sibling intimacy and conflict, beyond the effects of sex. Specifically, we applied the Actor-Partner Interdependence Model via multilevel modeling to 5 years of longitudinal data, collected in home interviews from two adolescent-aged siblings from 194 families, to assess links between older (M-age = 16.47 SD = .80) and younger (M-age = 13.88, SD = 1.15) siblings' stereotypically feminine, expressive (e.g., kindness, sensitivity) characteristics and their ratings of sibling intimacy and conflict. Results indicated that youth's expressivity was related positively to their reports of sibling intimacy and negatively to their reports of sibling conflict. Controlling for biological sex, sibling intimacy reached its highest levels and sibling conflict was at its lowest, when both siblings reported high expressivity. On a practical level, these findings illuminate malleable behaviors and characteristics that may promote harmonious sibling relationships, a significant goal given that siblings can serve as sources of support and care in adolescence and beyond.